The specific aims of this proposal are designed to answer fundamental questions about the regulation of the follicle-stimulating hormone receptor (FSHR) gene in vivo. A defined series of reporter constructs that consist of the human growth hormone gene driven by various lengths of the FSHR promoter will be used to determine the role of specific regions of the promoter in mediating expression in vivo. Comparison of the expression of the transgene in Sertoli and granulosa cells will determine if different regions of the promoter are necessary for expression in these cell types and elucidate the relative importance of specific regulatory regions of the promoter. Additional experiments will determine a region of the promoter that is necessary for Sertoli and granulosa cell specific expression in vivo. Finally, experiments are designed to test the hypothesis that the cell specific expression of the FSHR gene is regulated by methylation.